If you take the route suggested by Attack man (which is just as good as any other route, IMO), you can buy Michigan trail passes at Dietz's gas station in Manitowish Waters, WI, or at Karsyn’s Korner (formely Thoma’s Mini Mart - I think its still a BP gas station) in Presque Isle, WI. You could also take the Bearskin into Minocqua and jump on the 17 grade in Minocqua for the run up to Mercer. (When approaching Minocqua, stay to the West of Hwy.51 9i.e., don't go under the Hwy.51 bridge) and get off Lake Minocqua at Hwy 70 and go West a few blocks to pick up 10 North, which will intersect right away with the 17 grade trail.)